TiredCord is bulky compared to the rest of the device. Diffuser attachment is only so-so. High price causes hesitation. Sure, this product took four years to engineer and the results are fantastic. But $400 nearly doubles the industry average for professional-grade hair dryers, and that's a big jump.

TiredCord is bulky compared to the rest of the device. Diffuser attachment is only so-so. High price causes hesitation. Sure, this product took four years to engineer and the results are fantastic. But $400 nearly doubles the industry average for professional-grade hair dryers, and that's a big jump.

Hair dryers are the least glamorous part of looking glamorous. They're cumbersome, their cords tangle easily, and they devour precious drawer space. The cheap $20 ones barely get the job done, while $200 "professional" models only provide marginal improvements on the same old technology.

Dyson, the brand behind those pricey, highly engineered vacuums and fans, has taken a stab at this essential post-shower tool. The Supersonic hair dryer reinvigorates an underserved category with a masterpiece of efficiency that blows away the competition.

The Supersonic is compact; not "travel size," but small enough to fit into a carry-on bag without having to sacrifice a day's clothes. Inside you'll find a tiny, but powerful, motor—the same technology Dyson employs in its bladeless fans—that produces a strong, even flow of hot air.

Its placement makes the Supersonic easier to handle. Hair dryers have used the classic L-shape for decades, with the large motor—and hence the mass—off-center at the top of the handle. Dyson put the motor in the handle, giving the Supersonic superlative balance that makes it feel lighter. Professional stylists who use their hair dryers all day will love it, but even for regular folks, it's a welcome improvement.

Three styling attachments—two to direct airflow, and a diffuser—snap onto the handle with magnets. You can rotate the attachments and swap them quickly and easily. The dryer works without them, but they're handy if you need to direct airflow at a brush, or spread it out to get well-defined curls. One quibble: The cord is a bit bulky, but that seems designed to resist tangling.

Not Just Hot Air

The Supersonic uses a microprocessor to monitor heat output, and a constant feedback loop to ensure consistent temperature. That could sound like some serious over-engineering, but the ability to maintain consistent heat noticeably improves shine and definitely dries hair faster.

A pair of buttons on the back of the barrel adjust the temperature and fan speed. Their placement is an unsung design win for Dyson. Your typical hair dryer features two toggling switches: one for temperature and one for speed. The fancier the hair dryer, the more settings you have. You almost always find these switches on the side of handle (under your thumb), or on the front, like the trigger of a pistol. That might be useful in a shootout, but when you're drying hair, you tend to pick a setting and let it be. Until, of course, your finger inevitably hits one of the switches, speeding up the fan or cranking up the heat. Dyson's placement mitigates this risk.

The Supersonic offers three speeds and three temperatures. The max level serious oomph—Dyson's experience controlling airflow is on full display here. You'll find the power button on the handle, and, in a cool trick, the Supersonic saves your preferred settings when you switch it off.

Like all Dyson products, the Supersonic is pricey at $400. But you get truly superior engineering and well-considered design. Sure, these are small changes to a familiar product, but if drying your hair is a part of your daily routine, the Supersonic make it more efficient and delivers more consistent results. When you're running late for your morning meeting or a dinner reservation, you'll appreciate those frustration-free minutes.